This has been brought up before, but I think this explanation is different.
It would be interesting to see some stats and graphs on tag trends.
Please note, this would go beyond the data currently available under tag details.
If there was a simple and secure way to
build queries to access these stats (similar to JIRA's filtering), it could become a very powerful tool.
Personally, I've noticed differences in topics that are popping up at different times of day. It would be interesting to see what sort of developers tend to be around the site at
specific time periods. This could also provide insights into
specializations across the globe.
These would be live, more descriptive, and perhaps interactive.